scholarly journals Membrane-active Polymers: NCMNP13-x, NCMNP21-x and NCMNP21b-x for Membrane Protein Structural Biology

2022 ◽  
Author(s):  
Thi Kim Hoang Trinh ◽  
Claudio Catalano ◽  
Youzhong Guo

Membrane proteins are a ubiquitous group of bio-macromolecules responsible for many crucial biological processes and serve as drug targets for a wide range of modern drugs. Detergent-free technologies such as styrene-maleic acid lipid particles (SMALP), diisobutylene-maleic acid lipid particles (DIBMALP), and native cell membrane nanoparticles (NCMN) systems have recently emerged as revolutionary alternatives to the traditional detergent-based approaches for membrane protein research. NCMN systems aim to create a membrane-active polymer library suitable for high-resolution structure determination. Herein, we report our design, synthesis, characterization and comparative application analyses of three novel classes of NCMN polymers, NCMNP13-x, NCMNP21-x and NCMNP21b-x. Although each NCMN polymer can solubilize various model membrane proteins and conserve native lipids into NCMN particles, only the NCMNP21b-x series reveals lipid-protein particles with good buffer compatibility and high homogeneity suitable for single-particle cryo-EM analysis. Consequently, the NCMNP21b-x polymers that bring out high-quality NCMN particles are particularly attractive for membrane protein structural biology.

Author(s):  
Youzhong Guo

Membrane proteins play vital roles in living organisms, serving as targets for most currently prescribed drugs. Membrane protein structural biology aims to provide accurate structural information to understand their mechanisms of action. The advance of membrane protein structural biology has primarily relied on detergent-based methods over the past several decades. However, detergent-based approaches have significant drawbacks because detergents often damage the native protein–lipid interactions, which are often crucial for maintaining the natural structure and function of membrane proteins. Detergent-free methods recently have emerged as alternatives with a great promise, e.g. for high-resolution structure determinations of membrane proteins in their native cell membrane lipid environments. This minireview critically examines the current status of detergent-free methods by a comparative analysis of five groups of membrane protein structures determined using detergent-free and detergent-based methods. This analysis reveals that current detergent-free systems, such as the styrene-maleic acid lipid particles (SMALP), the diisobutyl maleic acid lipid particles (DIBMALP), and the cycloalkane-modified amphiphile polymer (CyclAPol) technologies are not better than detergent-based approaches in terms of maintenance of native cell membrane lipids on the transmembrane domain and high-resolution structure determination. However, another detergent-free technology, the native cell membrane nanoparticles (NCMN) system, demonstrated improved maintenance of native cell membrane lipids with the studied membrane proteins, and produced particles that were suitable for high-resolution structural analysis. The ongoing development of new membrane-active polymers and their optimization will facilitate the maturation of these new detergent-free systems.


2011 ◽  
Vol 39 (3) ◽  
pp. 719-723 ◽  
Author(s):  
Zharain Bawa ◽  
Charlotte E. Bland ◽  
Nicklas Bonander ◽  
Nagamani Bora ◽  
Stephanie P. Cartwright ◽  
...  

Membrane proteins are drug targets for a wide range of diseases. Having access to appropriate samples for further research underpins the pharmaceutical industry's strategy for developing new drugs. This is typically achieved by synthesizing a protein of interest in host cells that can be cultured on a large scale, allowing the isolation of the pure protein in quantities much higher than those found in the protein's native source. Yeast is a popular host as it is a eukaryote with similar synthetic machinery to that of the native human source cells of many proteins of interest, while also being quick, easy and cheap to grow and process. Even in these cells, the production of human membrane proteins can be plagued by low functional yields; we wish to understand why. We have identified molecular mechanisms and culture parameters underpinning high yields and have consolidated our findings to engineer improved yeast host strains. By relieving the bottlenecks to recombinant membrane protein production in yeast, we aim to contribute to the drug discovery pipeline, while providing insight into translational processes.


2021 ◽  
Vol 28 ◽  
Author(s):  
Chen-Yan china Zhang ◽  
Shi-Qi Zhao ◽  
Shi-Long Zhang ◽  
Li-Heng Luo ◽  
Ding-Chang Liu ◽  
...  

: Membrane proteins are crucial for biological processes, and many of them are important to drug targets. Understanding the three-dimensional structures of membrane proteins are essential to evaluate their bio function and drug design. High-purity membrane proteins are important for structural determination. Membrane proteins have low yields and are difficult to purify because they tend to aggregate. We summarized membrane protein expression systems, vectors, tags, and detergents, which have deposited in the Protein Data Bank (PDB) in recent four-and-a-half years. Escherichia coli is the most expression system for membrane proteins, and HEK293 cells are the most commonly cell lines for human membrane protein expression. The most frequently vectors are pFastBac1 for alpha-helical membrane proteins, pET28a for beta-barrel membrane proteins, and pTRC99a for monotopic membrane proteins. The most used tag for membrane proteins is the 6×His-tag. FLAG commonly used for alpha-helical membrane proteins, Strep and GST for beta-barrel and monotopic membrane proteins, respectively. The detergents and their concentrations used for alpha-helical, beta-barrel, and monotopic membrane proteins are different, and DDM is commonly used for membrane protein purification. It can guide the expression and purification of membrane proteins, thus contributing to their structure and bio function studying.


2018 ◽  
Vol 47 (1) ◽  
pp. 47-61 ◽  
Author(s):  
Rosana Reis ◽  
Isabel Moraes

Abstract The study of structure–function relationships of membrane proteins (MPs) has been one of the major goals in the field of structural biology. Many Noble Prizes regarding remarkable accomplishments in MP structure determination and biochemistry have been awarded over the last few decades. Mutations or improper folding of these proteins are associated with numerous serious illnesses. Therefore, as important drug targets, the study of their primary sequence and three-dimensional fold, combined with cell-based assays, provides vital information about their structure–function relationships. Today, this information is vital to drug discovery and medicine. In the last two decades, many have been the technical advances and breakthroughs in the field of MP structural biology that have contributed to an exponential growth in the number of unique MP structures in the Protein Data Bank. Nevertheless, given the medical importance and many unanswered questions, it will never be an excess of MP structures, regardless of the method used. Owing to the extension of the field, in this brief review, we will only focus on structure–function relationships of the three most significant pharmaceutical classes: G protein-coupled receptors, ion channels and transporters.


Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 401
Author(s):  
James Birch ◽  
Harish Cheruvara ◽  
Nadisha Gamage ◽  
Peter J. Harrison ◽  
Ryan Lithgo ◽  
...  

Membrane proteins are essential components of many biochemical processes and are important pharmaceutical targets. Membrane protein structural biology provides the molecular rationale for these biochemical process as well as being a highly useful tool for drug discovery. Unfortunately, membrane protein structural biology is a difficult area of study due to low protein yields and high levels of instability especially when membrane proteins are removed from their native environments. Despite this instability, membrane protein structural biology has made great leaps over the last fifteen years. Today, the landscape is almost unrecognisable. The numbers of available atomic resolution structures have increased 10-fold though advances in crystallography and more recently by cryo-electron microscopy. These advances in structural biology were achieved through the efforts of many researchers around the world as well as initiatives such as the Membrane Protein Laboratory (MPL) at Diamond Light Source. The MPL has helped, provided access to and contributed to advances in protein production, sample preparation and data collection. Together, these advances have enabled higher resolution structures, from less material, at a greater rate, from a more diverse range of membrane protein targets. Despite this success, significant challenges remain. Here, we review the progress made and highlight current and future challenges that will be overcome.


2016 ◽  
Vol 44 (4) ◽  
pp. 1011-1018 ◽  
Author(s):  
Sarah C. Lee ◽  
Naomi L. Pollock

The use of styrene maleic acid lipid particles (SMALPs) for the purification of membrane proteins (MPs) is a rapidly developing technology. The amphiphilic copolymer of styrene and maleic acid (SMA) disrupts biological membranes and can extract membrane proteins in nanodiscs of approximately 10 nm diameter. These discs contain SMA, protein and membrane lipids. There is evidence that MPs in SMALPs retain their native structures and functions, in some cases with enhanced thermal stability. In addition, the method is compatible with biological buffers and a wide variety of biophysical and structural analysis techniques. The use of SMALPs to solubilize and stabilize MPs offers a new approach in our attempts to understand, and influence, the structure and function of MPs and biological membranes. In this review, we critically assess progress with this method, address some of the associated technical challenges, and discuss opportunities for exploiting SMA and SMALPs to expand our understanding of MP biology.


2002 ◽  
Vol 80 (5) ◽  
pp. v-xi ◽  
Author(s):  
James D Young ◽  
Joseph R Casey ◽  
Reinhart A.F Reithmeier

This article summarizes the scientific presentations made at a Canadian Society of Biochemistry and Molecular & Cellular Biology Symposium on "Membrane Proteins in Health and Diseases" and two satellite meetings on "Bicarbonate Transporters" and "Nucleoside Transporters" held in Banff, Alberta, 20–24 March 2002. Membrane proteins are encoded by about 1/3 of genes and are involved in a wide range of essential functions, including the transport of nutrients, ions, and waste products across biological membranes. Mutations or changes in the expression of these genes cause an equally wide range of diseases. Membrane proteins are also common drug targets or provide drug entry mechanisms. The importance of membrane proteins in biology and medicine was highlighted by the presentations made at this exciting meeting by an international group of experts.Key words: bicarbonate, genomics, inherited disease, nucleosides, organelles, pH regulation, structural biology, trafficking, transporters.


2020 ◽  
Author(s):  
Rong Guo ◽  
Jacob Sumner ◽  
Shuo Qian

Diisobutylene maleic acid (DIBMA) has been shown to solubilize and purify membrane proteins from a native lipid bilayer into nanodiscs without the need for a detergent. To explore DIBMA lipid particles as a suitable membrane mimetic system for neutron scattering studies of membrane proteins, we measured and determined the contrast matching point of DIBMA to be ~12% (v/v) D2O—similar to that of most protiated lipid molecules, but distinct from that of regular protiated proteins, providing a natural contrast for separating neutron scattering signals. Using SANS contrast variation, we demonstrated that the scattering from the whole lipid particle can be annihilated. Further, the lipid part of the particle shows a well-defined discoidal shape with DIBMA contrast matched. These results demonstrate that the DIBMA lipid particle is an outstanding “stealth” membrane mimetic for membrane proteins.<br>


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Gabriella Angiulli ◽  
Harveer Singh Dhupar ◽  
Hiroshi Suzuki ◽  
Irvinder Singh Wason ◽  
Franck Duong Van Hoa ◽  
...  

Previously we introduced peptidiscs as an alternative to detergents to stabilize membrane proteins in solution (Carlson et al., 2018). Here, we present ‘on-gradient’ reconstitution, a new gentle approach for the reconstitution of labile membrane-protein complexes, and used it to reconstitute Rhodobacter sphaeroides reaction center complexes, demonstrating that peptidiscs can adapt to transmembrane domains of very different sizes and shapes. Using the conventional ‘on-bead’ approach, we reconstituted Escherichia coli proteins MsbA and MscS and find that peptidiscs stabilize them in their native conformation and allow for high-resolution structure determination by cryo-electron microscopy. The structures reveal that peptidisc peptides can arrange around transmembrane proteins differently, thus revealing the structural basis for why peptidiscs can stabilize such a large variety of membrane proteins. Together, our results establish the gentle and easy-to-use peptidiscs as a potentially universal alternative to detergents as a means to stabilize membrane proteins in solution for structural and functional studies.


2021 ◽  
Author(s):  
Robert D Healey ◽  
Shibom Basu ◽  
Anne-Sophie Humm ◽  
Cedric Leyrat ◽  
Xiaojing Cong ◽  
...  

Membrane proteins are central to many pathophysiological processes yet remain very difficult to analyze at a structural level. Moreover, high-throughput structure-based drug discovery has not yet been exploited for membrane proteins due to lack of automation. Here, we present a facile and versatile platform for in meso membrane protein crystallization, enabling rapid atomic structure determination at both cryogenic and room temperature and in a single support. We apply this approach to two human integral membrane proteins, which allowed us to capture different conformational states of intramembrane enzyme-product complexes and analyze the structural dynamics of the ADIPOR2 integral membrane protein. Finally, we demonstrate an automated pipeline combining high-throughput microcrystal soaking, automated laser-based harvesting and serial crystallography enabling screening of small molecule libraries with membrane protein crystals grown in meso. This approach brings badly needed automation for this important class of drug targets and enables high-throughput structure-based ligand discovery with membrane proteins.


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